Last week, along with the rest of the seniors at Stafford High School in Falmouth, Virginia, 18-year-old Diana Bloom got her yearbook.

Bloom was flipping through the yearbook when she noticed a very special student.

"Seeing a picture of a dog caught my eye pretty quickly," Bloom told BuzzFeed News. "I thought it was so cute, and I knew that some of my underclassmen friends hadn't seen it yet because they didn't have their yearbooks, so I took a picture and tweeted it."

Her tweet has since been retweeted more than 2,500 times.

This very good student is called Alpha, and he's a service dog for Andrew "AJ" Schalk, a 16-year-old junior at Stafford High.

AJ Schalk

Bloom said she and Schalk ride the same bus but don't have any classes together, so she didn't know that Alpha would be appearing in the yearbook.

Schalk told BuzzFeed News that he has type 1 diabetes and Alpha's job is to alert him when his blood sugar is getting too low or high.

AJ Schalk

"The amazing thing about Alpha is that he knows 20 to 40 minutes before my blood sugar actually does go low or high due to his amazing sense of smell," he said.

"He has saved my life multiple times already, by waking me up in the middle of the night to extremely low blood sugars, which are very dangerous," Schalk said.

AJ Schalk

He said he started bringing Alpha to school with him last year "to get him acclimated to the school environment so he would be prepared for this year."

AJ Schalk

"He has become a huge part of my school, coming to my classes with me, and a lot of people know about him," Schalk said. So he spoke to the people in charge of the yearbook to see if Alpha could be included.

AJ Schalk

"All the teachers and students were 100% supportive," Schalk said.

"I just brought him with me when I got my yearbook picture taken," Schalk said. "The only thing they changed was the camera height. They just had to lower it a little, haha."

Alpha even got his own school ID.

AJ Schalk

"He has been a great companion and added a lot of happiness to my school's environment," Schalk said. "It brightens people's days seeing him in the halls or in my class and I love being able to have that effect on people."

Diana Bloom

People absolutely love it.

"Yes, Alpha is really an amazing animal," Schalk said. "He makes a disability, such as my diabetes, such a positive experience for me and my life overall, and really turns it into a blessing rather than a negative part of my life."